Oil rose to the highest level in almost six months as the US government was said to eliminate sanction waivers that allowed buyers to import Iranian crude.

Futures in London jumped as much as 3.3% to the highest intraday price since early November. Secretary of State Mike Pompeo on Monday will deliver the decision that no waivers from sanctions will be renewed to importers of Iranian oil, according to four people familiar with the matter.

The US will also announce offsets through commitments from other suppliers such as Saudi Arabia and the United Arab Emirates.

Benchmark Brent has gained about 37% this year as the Organisation of Petroleum Exporting Countries (OPEC) and its allies, including Russia, continued their commitment to curb output in a bid to avert a glut.

US sanctions on Iran and Venezuela, along with unexpected losses in Libya, have squeezed supplies further. Signs of slowing production growth in the US and disruption at a key Nigerian pipeline are also bolstering bullish sentiment.

"It's a very critical time, a couple of weeks ahead of the expiration of waivers to the sanctions," said Edward Bell, commodities analyst at Dubai-based bank Emirates NBD PJSC. "The market was looking for some kind of announcement or news rather than the uncertainty we have been dealing with in the last six months."

Brent for June settlement climbed as much as $2.34 to $74.31 a barrel on the London-based ICE Futures Europe exchange and was at $73.66 a barrel at 1:31pm in Dubai. The contract rose 35 cents on Thursday, capping a fourth weekly advance. No futures were traded in London or New York on Friday due to the Good Friday holiday.

West Texas Intermediate for May delivery, which will expire Monday, rose as much as $1.87 to $65.87 a barrel on the New York Mercantile Exchange, while the more-active June contract gained 3 percent to $65.99. WTI was at a discount of $8.25 to Brent for the same month.

The Trump administration's decision to not extend waivers comes after National Security Adviser John Bolton and his allies argued that US promises to get tough on the Persian Gulf state were meaningless with the exemptions still in place. The current set of waivers - issued to China, India, Japan, South Korea, Italy, Greece, Turkey and Taiwan - will expire in less than two weeks.

South Korea's Hanwha Total Petrochemical, a buyer of Iranian ultra-light oil, has already been buying and testing alternative oil cargoes from regions such as Africa and Australia, said a company spokesperson who asked not to be identified because of internal policy. The company is currently waiting for an official response from the government on the waivers.

In the US, working oil rigs fell by eight last week to 825 as explorers reduced activity in American fields for the first time in April amid investor demand for spending discipline. Drillers in the Permian Basin idled one rig, while rigs from the Eagle Ford remained unchanged.

Further gains in oil prices would hinge on Russia's stance on the output-reduction pact, said Kim Kwangrae, a commodities analyst at Samsung Futures in Seoul.

Russian Energy Minister Alexander Novak said last week that it's too early to talk about possible options for the group with regard to the future of the cuts. There would likely be discussions about whether OPEC and its allies would extend production curbs at their meeting in Jeddah next month, Novak said.